In the manufacture of integrated circuits there is an increasing use of redundant circuit elements to increase the yield of good circuits. There is also a growing trend to customize standard integrated circuits after fabrication of the circuits. The integrated circuits manufactured for these purposes can include fusible links which are selectively opened after the circuit has been probe tested or its function has been determined.
In a conventional fuse link circuit, a control terminal in the integrated circuit is connected through a current limiting device to a first power terminal and at the same time connected through a fusible link to a second power terminal. The desired voltage state of the control terminal is selected by either opening or not opening the fusible link. This approach, however, results in a DC current flow through the current limiting device and the fusible link for those links which are not opened. This static power consumption can be a substantial problem for integrated circuits where power consumption is a critical parameter.
CMOS (complementary metal oxide semiconductor) circuits are particularly desirable because they can be designed to have low power consumption. However, this advantage is offset when conventional fusible links and current limiting devices are utilized to program the integrated circuit. Therefore, there exists a need for a method and apparatus for programming integrated circuits, particulary CMOS circuits, in which the static power consumption of the programmable elements is significantly reduced or eliminated.